Picture frame



FIG. 1 is a front perspective view of a picture frame showing my new design;

FIG. 2 is a bottom, rear perspective view thereof;

FIG. 3 is a top, rear perspective view thereof;

FIG. 4 is a side elevational view thereof; and

FIG. 5 is an exploded perspective view thereof. 

The ornamental design for a picture frame, as shown and described. 